Nitrofurant Mac 25mg Capsules
It is used to treat or prevent a urinary tract infection (UTI).
Drug Class
Urinary Anti-infective
Pharmacologic Class
Nitrofuran derivative
Pregnancy Category
Not available
FDA Approved
Mar 1953
DEA Schedule
Not Controlled
Overview
What is this medicine?
Nitrofurantoin is an antibiotic used to treat and prevent urinary tract infections (UTIs). It works by stopping the growth of bacteria in the urine. It's important to take it exactly as prescribed, usually with food, to help it work better and reduce stomach upset.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication with food to help your body absorb it properly. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
It's also important to stay hydrated by drinking plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. However, avoid taking antacids that contain magnesium trisilicate while taking this medication, as they may interact with it.
Storing and Disposing of Your Medication
To keep your medication effective and safe, store it at room temperature in a dry place, away from the bathroom. Keep all medications out of the reach of children and pets to avoid accidents. When you're finished with your medication or it expires, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. If you're unsure about how to dispose of your medication, ask your pharmacist for guidance. You may also want to check if there are any drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication with food to help your body absorb it properly. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
It's also important to stay hydrated by drinking plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. However, avoid taking antacids that contain magnesium trisilicate while taking this medication, as they may interact with it.
Storing and Disposing of Your Medication
To keep your medication effective and safe, store it at room temperature in a dry place, away from the bathroom. Keep all medications out of the reach of children and pets to avoid accidents. When you're finished with your medication or it expires, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. If you're unsure about how to dispose of your medication, ask your pharmacist for guidance. You may also want to check if there are any drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed one.
Lifestyle & Tips
- Take with food or milk to improve absorption and reduce stomach upset.
- Drink plenty of fluids unless otherwise directed by your doctor.
- Complete the full course of medication, even if symptoms improve, to prevent recurrence and antibiotic resistance.
- Urine may turn dark yellow or brown; this is a harmless side effect.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
For treatment of acute uncomplicated UTI: 50-100 mg four times daily for 7 days. For prophylaxis of recurrent UTI: 50-100 mg once daily at bedtime. Note: 25mg capsules are typically used for prophylaxis or specific low-dose regimens.
Dose Range:
25 - 100 mg
Condition-Specific Dosing:
acute_uncomplicated_uti_treatment:
50-100 mg four times daily for 7 days
recurrent_uti_prophylaxis:
50-100 mg once daily at bedtime
Pediatric Dosing
Neonatal:
Not established (contraindicated in infants <1 month of age due to risk of hemolytic anemia)
Infant:
Not established (contraindicated in infants <1 month of age). For infants >1 month, treatment: 5-7 mg/kg/day in 4 divided doses. Prophylaxis: 1-2 mg/kg/day once daily.
Child:
Treatment: 5-7 mg/kg/day in 4 divided doses. Prophylaxis: 1-2 mg/kg/day once daily.
Adolescent:
Treatment: 50-100 mg four times daily for 7 days. Prophylaxis: 50-100 mg once daily at bedtime.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment, but caution advised.
Moderate:
Contraindicated if CrCl <60 mL/min due to lack of efficacy and increased risk of toxicity.
Severe:
Contraindicated if CrCl <60 mL/min.
Dialysis:
Contraindicated (ineffective and increased toxicity).
Hepatic Impairment:
Mild:
Use with caution; monitor liver function tests.
Moderate:
Use with caution; monitor liver function tests. Increased risk of hepatotoxicity.
Severe:
Use with caution; monitor liver function tests. Increased risk of hepatotoxicity.
Pharmacology
Mechanism of Action
Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates that inactivate or damage bacterial ribosomal proteins, DNA, RNA, and other macromolecules. This leads to inhibition of bacterial growth and cell death. Its antibacterial activity is specific to the urinary tract.
Pharmacokinetics
Absorption:
Bioavailability:
Not precisely quantified, but well absorbed.
Tmax:
Approximately 4 hours (macrocrystals)
FoodEffect:
Absorption is enhanced and peak plasma concentrations are reduced when taken with food, which improves tolerability and prolongs therapeutic concentrations in the urine.
Distribution:
Vd:
Not available
ProteinBinding:
Approximately 60%
CnssPenetration:
Limited
Elimination:
HalfLife:
0.3 to 1 hour
Clearance:
Rapid renal clearance
ExcretionRoute:
Primarily renal (glomerular filtration and tubular secretion)
Unchanged:
20-40% (in urine)
Pharmacodynamics
OnsetOfAction:
Rapid (within hours for urinary concentrations)
PeakEffect:
Not directly applicable for systemic effect, but urinary concentrations peak within hours.
DurationOfAction:
Sustained urinary concentrations for several hours due to slow absorption of macrocrystals.
Confidence:
Medium
Safety & Warnings
BLACK BOX WARNING
Pulmonary Toxicity: Acute, subacute, or chronic pulmonary reactions have been observed in patients treated with nitrofurantoin. If these reactions occur, nitrofurantoin should be discontinued and appropriate measures taken. Chronic pulmonary reactions (diffuse interstitial pneumonitis or pulmonary fibrosis) can develop insidiously and are more common in patients receiving long-term therapy. Hepatotoxicity: Hepatic reactions, including cholestatic jaundice and chronic active hepatitis, are rare but severe. Fatalities have been reported. Patients should be monitored for signs and symptoms of liver injury.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Rarely, allergic reactions can be fatal.
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of lupus, such as:
+ Rash on the cheeks or other body parts
+ Easy sunburn
+ Muscle or joint pain
+ Chest pain or shortness of breath
+ Swelling in the arms or legs
Inability to control eye movements
Diarrhea, especially if it is severe or accompanied by:
+ Stomach pain
+ Cramps
+ Loose, watery, or bloody stools
+ Note: Diarrhea is common with antibiotics, but a severe form called C. diff-associated diarrhea (CDAD) can occur, which may lead to a life-threatening bowel problem.
Liver problems, which can be fatal, and may include:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Nerve problems, which can be severe, permanent, or fatal, and may include:
+ Burning sensation
+ Numbness
+ Tingling
+ Note: The risk of nerve problems may be higher in people with kidney problems, anemia, diabetes, electrolyte problems, or low vitamin B levels.
Other Possible Side Effects
Most people experience no side effects or only mild side effects while taking this medication. However, if you experience any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
Headache
Upset stomach or vomiting
Decreased appetite
Stomach pain or diarrhea
Dizziness
Drowsiness
Fatigue
Weakness
Hair loss (which may be reversible when the medication is stopped)
Urine color change to brown (which is normal and harmless)
Reporting Side Effects
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Rarely, allergic reactions can be fatal.
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of lupus, such as:
+ Rash on the cheeks or other body parts
+ Easy sunburn
+ Muscle or joint pain
+ Chest pain or shortness of breath
+ Swelling in the arms or legs
Inability to control eye movements
Diarrhea, especially if it is severe or accompanied by:
+ Stomach pain
+ Cramps
+ Loose, watery, or bloody stools
+ Note: Diarrhea is common with antibiotics, but a severe form called C. diff-associated diarrhea (CDAD) can occur, which may lead to a life-threatening bowel problem.
Liver problems, which can be fatal, and may include:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Nerve problems, which can be severe, permanent, or fatal, and may include:
+ Burning sensation
+ Numbness
+ Tingling
+ Note: The risk of nerve problems may be higher in people with kidney problems, anemia, diabetes, electrolyte problems, or low vitamin B levels.
Other Possible Side Effects
Most people experience no side effects or only mild side effects while taking this medication. However, if you experience any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
Headache
Upset stomach or vomiting
Decreased appetite
Stomach pain or diarrhea
Dizziness
Drowsiness
Fatigue
Weakness
Hair loss (which may be reversible when the medication is stopped)
Urine color change to brown (which is normal and harmless)
Reporting Side Effects
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- New or worsening cough, shortness of breath, chest pain, or fever (signs of lung problems)
- Unusual tiredness, loss of appetite, nausea, vomiting, dark urine, yellowing of skin or eyes (signs of liver problems)
- Numbness, tingling, burning pain, or weakness in hands or feet (signs of nerve damage)
- Severe diarrhea (especially if watery or bloody)
- Unusual bruising or bleeding, pale skin, extreme tiredness (signs of blood problems)
- Severe allergic reaction (rash, itching/swelling, severe dizziness, trouble breathing)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reactions you have experienced.
Kidney disease, as it may affect how your body processes this medication.
Difficulty urinating, as this may be a sign of an underlying condition that could interact with this medication.
Previous liver problems caused by this medication, as this may increase your risk of further liver damage.
Pregnancy, especially if you are 38 weeks or more pregnant, as this medication may affect your unborn baby.
Special Considerations for Children:
If the patient is a child under 1 month of age, do not administer this medication, as it is not approved for use in this age group.
Additional Precautions:
This medication may interact with other drugs, including prescription and over-the-counter medications, natural products, and vitamins. Provide your doctor and pharmacist with a comprehensive list of all your medications and health problems to ensure safe treatment.
Do not start, stop, or change the dose of any medication without consulting your doctor, as this may lead to adverse interactions or reduce the effectiveness of your treatment.
It is essential to inform your doctor about the following conditions to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reactions you have experienced.
Kidney disease, as it may affect how your body processes this medication.
Difficulty urinating, as this may be a sign of an underlying condition that could interact with this medication.
Previous liver problems caused by this medication, as this may increase your risk of further liver damage.
Pregnancy, especially if you are 38 weeks or more pregnant, as this medication may affect your unborn baby.
Special Considerations for Children:
If the patient is a child under 1 month of age, do not administer this medication, as it is not approved for use in this age group.
Additional Precautions:
This medication may interact with other drugs, including prescription and over-the-counter medications, natural products, and vitamins. Provide your doctor and pharmacist with a comprehensive list of all your medications and health problems to ensure safe treatment.
Do not start, stop, or change the dose of any medication without consulting your doctor, as this may lead to adverse interactions or reduce the effectiveness of your treatment.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you have a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), you may be at a higher risk of developing anemia. Individuals of African, South Asian, Middle Eastern, and Mediterranean descent are more likely to have low G6PD levels.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing methods for you. Do not take this medication for a longer period than prescribed, as this may increase the risk of a secondary infection.
Although rare, this medication has been associated with severe and potentially life-threatening lung problems, particularly in patients who have taken it for 6 months or longer. These lung problems can occur without warning signs. If you are taking this medication long-term, your doctor will monitor your lung function. Immediately contact your doctor if you experience symptoms such as fever, chills, chest pain, abnormal cough, difficulty breathing, or other respiratory problems.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Pregnant or breastfeeding women, or those planning to become pregnant, should discuss the potential benefits and risks of this medication with their doctor to ensure informed decision-making.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing methods for you. Do not take this medication for a longer period than prescribed, as this may increase the risk of a secondary infection.
Although rare, this medication has been associated with severe and potentially life-threatening lung problems, particularly in patients who have taken it for 6 months or longer. These lung problems can occur without warning signs. If you are taking this medication long-term, your doctor will monitor your lung function. Immediately contact your doctor if you experience symptoms such as fever, chills, chest pain, abnormal cough, difficulty breathing, or other respiratory problems.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Pregnant or breastfeeding women, or those planning to become pregnant, should discuss the potential benefits and risks of this medication with their doctor to ensure informed decision-making.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
What to Do:
In case of overdose, contact a poison control center immediately. Call 1-800-222-1222. Treatment is generally supportive; forced diuresis may be helpful.
Drug Interactions
Major Interactions
- Magnesium trisilicate-containing antacids (decreased absorption of nitrofurantoin)
- Probenecid and sulfinpyrazone (decreased renal excretion of nitrofurantoin, leading to increased systemic levels and decreased urinary efficacy)
- Live bacterial vaccines (e.g., Typhoid vaccine - may reduce therapeutic effect of vaccine)
Moderate Interactions
- Quinolone antibiotics (potential antagonism, though clinical significance is debated)
- Oral contraceptives (theoretical reduction in efficacy, but not well-established)
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: To ensure adequate renal clearance and avoid drug accumulation/toxicity; contraindicated if CrCl <60 mL/min.
Timing: Prior to initiation of therapy.
Liver function tests (LFTs)
Rationale: To assess baseline hepatic function, especially in patients with pre-existing liver disease or those on long-term therapy, due to risk of hepatotoxicity.
Timing: Prior to initiation of therapy, particularly for long-term use.
Complete Blood Count (CBC)
Rationale: To assess for baseline anemia or other hematologic abnormalities, especially in patients with G6PD deficiency, due to risk of hemolytic anemia.
Timing: Prior to initiation of therapy, especially if G6PD status is unknown or suspected.
Routine Monitoring
Liver function tests (LFTs)
Frequency: Periodically, especially with long-term therapy (e.g., every 3-6 months or as clinically indicated).
Target: Within normal limits.
Action Threshold: Significant elevation (e.g., >3x ULN) warrants discontinuation and investigation.
Pulmonary function tests (PFTs)
Frequency: Consider for patients on long-term therapy or those developing respiratory symptoms.
Target: Within normal limits or stable.
Action Threshold: New or worsening respiratory symptoms or significant decline in PFTs warrants discontinuation.
Complete Blood Count (CBC)
Frequency: Periodically, especially with long-term therapy or if hemolytic anemia is suspected.
Target: Within normal limits.
Action Threshold: Significant drop in hemoglobin/hematocrit or signs of hemolysis warrants investigation and discontinuation.
Symptom Monitoring
- Signs of pulmonary toxicity (e.g., cough, dyspnea, chest pain, fever, chills)
- Signs of hepatotoxicity (e.g., fatigue, anorexia, nausea, vomiting, dark urine, jaundice, right upper quadrant pain)
- Signs of peripheral neuropathy (e.g., numbness, tingling, weakness)
- Signs of hemolytic anemia (e.g., pallor, fatigue, dark urine, jaundice)
- Signs of allergic reaction (e.g., rash, itching, swelling, severe dizziness, trouble breathing)
Special Patient Groups
Pregnancy
Generally considered safe for use in the first and second trimesters for UTI treatment. However, it is contraindicated at term (38-42 weeks gestation) and during labor and delivery due to the theoretical risk of hemolytic anemia in the neonate, especially in infants with immature enzyme systems or G6PD deficiency.
Trimester-Specific Risks:
First Trimester:
Low risk; generally considered compatible.
Second Trimester:
Low risk; generally considered compatible.
Third Trimester:
Contraindicated at term (38-42 weeks) and during labor/delivery due to risk of neonatal hemolytic anemia.
Lactation
Generally considered compatible with breastfeeding, but caution is advised. Avoid use in infants with G6PD deficiency or in infants younger than 1 month of age due to the theoretical risk of hemolytic anemia.
Infant Risk:
Low risk for most healthy, full-term infants. Higher risk for G6PD deficient or very young (<1 month) infants.
Pediatric Use
Contraindicated in infants younger than 1 month of age. Use with caution in older pediatric patients, adjusting dose by weight. Long-term use in children should be carefully monitored for pulmonary and hepatic toxicities.
Geriatric Use
Increased risk of pulmonary toxicity, hepatotoxicity, and peripheral neuropathy, especially with long-term use. Renal function often declines with age, increasing the risk of drug accumulation and toxicity; contraindicated if CrCl <60 mL/min.
Clinical Information
Clinical Pearls
- Nitrofurantoin is a urinary-specific antibiotic; it does not achieve therapeutic concentrations in systemic tissues, making it unsuitable for pyelonephritis or other systemic infections.
- Always take with food to enhance absorption and reduce gastrointestinal side effects.
- Counsel patients about potential urine discoloration (dark yellow/brown), which is harmless.
- Emphasize the importance of reporting any new or worsening cough, shortness of breath, or signs of liver injury due to the black box warnings for pulmonary and hepatic toxicity.
- Contraindicated in patients with a creatinine clearance (CrCl) less than 60 mL/min due to reduced efficacy and increased risk of systemic toxicity (e.g., peripheral neuropathy, pulmonary fibrosis).
Alternative Therapies
- Trimethoprim/sulfamethoxazole (Bactrim)
- Fosfomycin
- Pivmecillinam (not available in US)
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin - generally reserved for more complicated UTIs due to resistance concerns and side effects)
- Beta-lactam antibiotics (e.g., amoxicillin/clavulanate, cephalexin - depending on susceptibility)
Cost & Coverage
Average Cost:
Varies widely, typically $10-$50 per 30 capsules (25mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.